Connecting to CSC Supercomputers

This topic is about how to login to the CSC supercomputers.

All materials (c) 2020-2023 by CSC – IT Center for Science Ltd. This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 Unported License, http://creativecommons.org/licenses/by-sa/4.0/

Login via the web interfaces

  • A simple way to login to the Puhti supercomputer is via https://www.puhti.csc.fi
  • Use your CSC username and password
  • The web interface can be used, e.g., to launch GUI applications, browse files or open a command-line shell
    • The latter is useful if your computer does not have an SSH client, but you need command-line access to the supercomputer
  • Similar web interfaces are also available for Mahti and LUMI

Login with SSH

  • SSH is a terminal program that gives you command-line access on the CSC supercomputer
  • It is a versatile main interface to a supercomputer
    • Laptop ↔︎ Toyota, Supercomputer ↔︎ F1. F1 needs a specialist interface.
  • Please read this page for an introduction on how to log in with SSH
  • Plain SSH will not allow displaying remote graphics
    • The web interfaces are often best for this, but can be enabled also by X11-tunneling (additional installations required on Windows, see link above)

Moving files between a local computer and Puhti

  • scp and rsync are powerful command-line tools to copy files
    • scp works even in Windows Powershell (but rsync is missing)
    • e.g. scp filename cscusername@puhti.csc.fi:/scratch/project_xxxx
    • e.g. rsync -r foldername cscusername@puhti.csc.fi:/scratch/project_xxxx
    • rsync exists in MobaXterm but it removes write permissions of copied files
  • Sometimes a GUI tool for transferring files is more convenient
    • Nice tools are e.g. FileZilla and WinSCP (may require admin privileges)
    • MobaXterm also has a file transfer GUI (Tip: first, set persistent home directory)
    • The web interfaces can also be used to easily upload/download files

Advanced topic: Setting up SSH keys

  • Using SSH keys is easier and safer than using a password with every login
  • SSH keys can be easily used in Windows, Mac, Linux
  • Consult our tutorials on how to set up SSH keys for your account
    • Logging in to LUMI requires setting up an SSH key pair and registering the public key in My CSC
    • Adding SSH keys in MyCSC for Puhti and Mahti is also possible, but not currently a requirement for connecting

Advanced topic: Developing scripts remotely